Abstract Booklet 2006 - Swanson School of Engineering - University ...

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to review strategies for designing a flow distribution system for the coolant fluid, where pressure drop is low and phase change occurs as the exothermic reaction in the process channel proceeds. 2-2 Selectivity Improvement via Nitriding of Iron-Based Fischer-Tropsch Catalysts Michael Claeys, Mark E. Dry, Eric van Steen, Centre for Catalysis Research, University of Cape Town, SOUTH AFRICA Philip Gibson, Jakobus Visagie, Thato Motjope, Andre van Zyl, Sasol Technology R&D, SOUTH AFRICA Iron-based Fischer-Tropsch catalysts have been modified by nitriding at different conditions in an attempt to affect product selectivity towards valuable chemicals. Mildly pre-reduced catalyst samples nitrided with ammonia at elevated temperature showed largely improved formation of oxygenates compared to hydrogen reduced catalysts. In addition, and in contrast to early work reported by the Bureau of Mines, nitrided samples in this work also showed increased productivity for long chain 1- olefins. Nitriding was not found to affect overall catalyst activity, water gas shift activity, methane selectivity and chain growth. The beneficial effects of nitriding can however decay at Fischer-Tropsch conditions, possibly due to loss of nitrogen from the iron nitride phases upon formation of iron carbides. 2-3 The Direct Synthesis of Dimethyl Ether over Hybrid Catalysts Composed of Cu-Zn Based Catalysts and Solid Acid Catalysts Tae Jin Lee, Eun Jin Kim, No-Kuk Park, Gi Bo Han, Si Ok Ryu, Yeungnam University, National Research Laboratory, SOUTH KOREA Dimethyl ether (DME) is primarily used as an aerosol propellant or industrially important chemical intermediate because of its attractive physical properties. In view of the environmental protection, the substitution of DME is unavoidable. Recently, a great attention has been paid to its applications as a fuel additive for vehicles and household uses. DME can be not only burned in diesel engine with a modified fuel system at the same efficiency but also handled like liquefied petroleum gas (LPG). DME has been obtained directly from syngas. In this study, the direct synthesis of DME over hybrid catalysts was performed in the temperature range of 270-290°C. Space velocity (GHSV), molar ratio of [H 2 ]/[CO], and reaction pressure in the experiments were 3000-6000 ml/g-cat.h, 1.0, and 30-50 atm, respectively. Typically, the hybrid catalysts were composed of methanol dehydration catalyst and methanol synthesis catalyst, which were made by a physical mixing in various combinations. A series of hybrid catalysts were characterized by BET surface area and XRD analysis. 2-4 Performance of a Non-Sulphided Maximum Distillate Catalyst in Fischer-Tropsch Wax Hydrocracking Jack C.Q. Fletcher, Athanasios Kotsiopolis, Walter Bohringer, University of Cape Town, Catalysis Research, SOUTH AFRICA M. de Boer, Albemarle Catalysts Company B.V., NETHERLANDS C. Knottenbelt, The Petroleum Oil & Gas Corporation of South Africa Ltd, SOUTH AFRICA Fischer-Tropsch (F-T) based Gas-to-Liquids (GTL) processing is recognized as an industrially proven and economically competitive route to high quality diesel. Furthermore, it is generally accepted that for this purpose, GTL processing is most effective when comprising an F-T synthesis driven to wax production, followed by hydrocracking to produce middle-distillate products. Applying a CoMo/SiO 2 -Al 2 O 3 catalyst, optimised for hydrocracking crude oil refinery feedstocks in a sulphur-containing environment, to the processing of a linear paraffin F-T wax model compound, n-tetradecane, shows that a significant opportunity exists for utilisation of base metal catalyst, having the advantage of producing less branched hydrocracking products, i.e. high cetane number diesel via a hydrogenolytic cracking mechanism. A drawback of such a catalyst, if applied in nonsulphided form and in a non-sulphur containing environment, is the comparably high yield of light gases, in particular methane. It is shown, and proved by a simple kinetic model, that methane is formed via ‘methanolysis’, i.e. successive hydrogenolytic demethanisation reaction of the feed compounds, presumably of islands of metallic cobalt on the catalyst. 2-5 High Temperature Methanation Process-Revisited Niels Udengaard, Anders N. Olsen, Haldor Topsoe Inc., USA Christian Wix-Nielsen, Haldor Topsoe A/S, DENMARK The rising cost of natural gas has resulted in a strong interest in manufacturing of substitute natural gas (SNG) from the less costly and much more abundant coal. Methanation of synthesis gas mixtures derived from gasification of coal is an essential step in the manufacturing of SNG. Technologies and catalysts for the SNG process were developed and tested extensively during the 1970’s, when the energy costs were expected to increase to unseen levels. This did not happen and the interest in this technology vanished. A renewed interest today in shifting more energy consumption to coal has resulted in a revival of several of these SNG technologies. The knowledge gained over the years has been applied to the former technologies resulting in improved efficiency and lower investment cost. SESSION 3 COMBUSTION TECHNOLOGIES – 1: ADVANCING PC PLANTS TO NEAR-ZERO EMISSIONS 3-1 Deployment of Near-Zero-Emission USC PC Power Plants for CO 2 Reduction Tony Armor, John Wheeldon, Electric Power Research Institute, USA Ultra-supercritical PC plants are being built and operated in Europe and Japan with superheated steam conditions as high as 4100 psia and 1130°F. These plants are built with ferritic steels and this limits the maximum operating temperature. At US operating conditions and using bituminous coal, the efficiency of these plants is around 40 percent on a higher heating value basis. These plants are operating reliably and achieving high availabilities and low emissions. The AD700 program in Europe is developing materials and for USC plants with superheated steam conditions as high as 5000 psia and 1290°F and improving boiler and steam turbine designs. To exceed the temperature limit imposed by the ferritic steels, high-nickel alloys have to be used. A similar US-DOE program is investigating high-nickel alloys for temperatures of 1400°F, which are projected to achieve generating efficiencies as high as 48 percent (HHV). USC plants operating at these conditions will lower CO 2 emissions by 20 percent compared to the current designs. By producing less CO 2 , the new designs lower the cost of CO 2 capture. This paper reports on the operation of current USC PC plants, along with their thermal and environmental performance, and how these designs might be deployed in the US. How the more advanced USC PC designs might be deployed to achieve near-zero emission power plants is also discussed. 3-2 Requirements and Issues towards Obtainment of Ultra-Low NO x Levels Tony Facchiano, EPRI, USA Several power plants equipped with low-NO x burners and SCR systems are already obtaining NO x levels under 0.05 lb/MBtu when fired on sub-bituminous coal. However, the obtainment of near-zero levels, defined as equal or less than 0.01 lb/MBtu, will require significant development effort for both bituminous and sub-bituminous coals. This paper will examine the current state of combustion-based and post-combustion NO x control technologies and their accomplishments, operational and design issues currently precluding the obtainment of near-zero NO x levels, and the development needed to overcome these limitations. This paper will draw upon full-scale data and experiences, as well as pilot- and lab-scale efforts currently underway. Specific issues addressed will include limitations on pollutants that may be consequential to achieving ultra-low NO x levels (e.g., SO 3 , ammonia slip, PM-10, etc), instrumentation and control challenges, component reliability, and the impact of fuel properties and their variability. Consideration will be given to the existing fleet of coal-fired boilers, where furnace design limits combustion-based NO x mitigation levels and available access limits SCR reactor sizes. Also discussed will be the design of new plants with advanced steam conditions, where greater flexibility to reduce NO x emissions, albeit at increased costs and operational constraints, can be built into the system. 3-3 FGD Designs for High Efficiency: Current Status and Future Challenges George Offen, Charles Dene, John Wheeldon, Electric Power Research Institute, USA Robert Keeth, Washington Group International, USA Performance and field experience with new, high-efficiency flue gas desulfurization (FGD) systems will be reported. The information presented will be based on recent EPRI visits to sites that had installed the latest design upgrades at commercial scale or were testing them at large-scale pilot scale. On-site discussions and observations were used to determine the impacts that these design upgrades were having on day-to-day performance of emissions control systems as well as balance-of-plant impacts. Sites in Europe, Japan, and the United States were visited during the project, and a summary of the major observations will be provided. The paper will also present an assessment of the ability of these technologies to achieve Near Zero Emissions (NZE) goals and suggest additional measures that may be needed to meet this goal continuously. Qualitatively, NZE is defined as being virtually equivalent to emissions from gas-fired power plants, with the exception of CO 2 . It will be shown that state-of-the-art FGD systems achieve very low SO 2 emissions when operated optimally, but to maintain these levels continuously provisions may be needed to counter temporary deviations in performance. 3-4 Advanced Ultra-Supercritical Boiler Design and Boiler Materials James Kutney, The Babcock & Wilcox Company, USA 2
The U.S. pioneered development of supercritical technology with the first boiler commencing commercial operation in 1957. This 125-MW B&W Universal Pressure boiler located at Ohio Power Company's Philo plant delivered 675,000 lb/h steam at 4,550 psi. The steam was superheated to 1150°F with two reheats to 1050 and 1000°F. Also installed in the U.S. are 9 x 1300-MW units, the largest single supercritical units designed, including one that set a record for 607 continuous days of operation. B&W are an actively involved in the US-DOE s ultra supercritical boiler materials research program testing stronger more corrosion-resistant materials, such as highnickel alloys, necessary to progress to steam temperatures as high as 1400°F. Such progression is essential to preserving pulverized coal technology as the preferred choice for power generation. Applying these new materials will increase generating efficiency beyond that currently possible with ferritic steels and, by producing less carbon dioxide, new units will have lower the costs for carbon capture and sequestration. This paper will present results from the test programs to certify the new materials. Fire-side and steam-side corrosion data have been collected from a test loop in an operating boiler as well as from laboratory simulations, and material weldability and fabrication have been evaluated. The paper will also discuss how the materials under development will be incorporated into the design of new, more efficient boilers. 3-5 Post-Combustion CO 2 Capture from Pulverized Coal Plants John Wheeldon, Electric Power Research Institute; USA In response to concerns over global warming, technologies need to be developed that capture and store the CO 2 released by fossil-fueled power plants. A study carried out in 2000 and cofunded by the US-DOE and EPRI investigated the thermal and economic performance of supercritical pulverized coal (PC) combustion and an E-Gas integrated gasification combined cycle (IGCC), using bituminous coal both with and without CO 2 removal. The general conclusion was that for power plants with CO 2 capture, the technology with the lowest cost of electricity was IGCC with pre-combustion capture. An implied conclusion was that supercritical PC with post-combustion capture was not an economic or efficient way to proceed. Since the publication of that study, several improvements have been identified that enhance the thermal and economic performance of post-combustion CO 2 capture technology. Improvements include those to solvents, CO 2 capture plant equipment design, and integration of the CO 2 capture plant with the power plant to improve heat utilization. Once these improvements are incorporated into the DOE/EPRI study, it is shown that a PC plant using post-combustion capture can be competitive with IGCC using pre-combustion capture. This is especially the case for sub-bituminous coal where post-combustion capture may be the most economic choice. The latest study also shows a benefit in going to ultrasupercritical steam conditions. The higher efficiency of these PC plants lowers the amount of CO 2 produced and so lowers the cost of CO 2 capture. This information justifies continued effort to develop materials for use with steam cycles operating at higher temperatures and pressures. Significant benefits are also gained from improvements to CO 2 capture solvents and equipment design, so both these measures also warrant continued development effort. The paper reports on the improvements identified for PC plants incorporating postcombustion CO 2 capture and discusses improvements that may be made in the future. SESSION 4 ENVIRONMENTAL CONTROL TECHNOLOGIES: MERCURY ABSORPTION – 1 4-1 Effectiveness of Sulphur-Impregnated Activated Carbons Produced Using Different Impregnation Methods in Mercury Vapour Adsorption Laura Fuentes de Maria, Shitang Tong, Donald W. Kirk, Charles Q. Jia, University of Toronto, CANADA Adsorption technologies based on sulphur-impregnated activated carbons (SIACs) have been proven an efficient method for vapour-phase mercury removal at coal-fired power plants. The enhanced adsorption capacity of SIACs is often attributed to its high specific surface area and sulphur species. The effect of sulphur-impregnation methods, which can result in different sulphur species in SIACs, on mercury adsorption, is however not well understood. The present study evaluates the effectiveness of several SIACs produced from petroleum coke using different activation methods in the adsorption of vapour-phase elemental mercury. To analyze the effect of different sulphur species on the adsorption of mercury, four types of activated carbons are used, a commercially available sulphur-free activated carbon (VAC), a commercially available SIAC (BARRICK), and two adsorbents (FC1 and FC2) produced in our laboratory using oil-sands fluid coke as raw material. The mercury adsorption experiments are conducted using a laboratory scaled fixed-bed quartz reactor. A permeation device is used as the source of mercury vapour. Concentrations of mercury vapour are analyzed based on the dual gold amalgamation technique using a Cold Vapour Atomic Fluorescence Spectrophotometer (CVAFS). The adsorption capacity of the carbons is determined by analyzing mercury concentrations before and after adsorption. The effect of the temperature is studied in this work to better understand mercury adsorption mechanisms by SIACs. 3 4-2 A Novel Process for On-site Production of Mercury Sorbents Lawrence Bool, Chien-Chung Chao, David R. Thompson, Praxair, USA Activated carbon injection (ACI) represents a promising method reduce mercury emissions from coal-fired plants. In recent years Praxair has developed a flexible process to produce powder activated carbon (PAC) on-site using the plant’s pulverized coal. The process is very flexible, allowing both undoped and doped carbons to be easily produced from the same plant. Third party test results from slipstream tests at We Energies’ Pleasant Prairie Plant and Xcel Energy’s Comanche Station have shown removals of 90% or greater. Praxair has continued to refine the process to better understand the process conditions leading to good mercury capture while minimizing the PAC cost. Several parameters have been explored in detail and will be discussed. These parameters include the effect of dopant concentration on mercury capture, the effect of different parent coals on sorbent performance, and the effect of a two-step activation process. Additional work planned in cooperation with the U.S. DOE to mitigate the impact of PAC produced with the Praxair process on concrete properties will also be discussed. 4-3 Feasibility of Activated Char Production for Mercury Capture from Chicken Waste and Coal Wei-Ping Pan, Hong Cui, Yan Cao, Institute for Combustion Science and Environmental Technology, Western Kentucky University, USA Chicken waste (CW) and its blending samples with a selected high sulfur coal (E-coal) were used as raw materials for activated char (AC) preparation. Raw samples were subjected to the preparation procedures of carbonization in a nitrogen atmosphere and activation in a steam atmosphere. The basic properties of the raw materials, char and activated char were analyzed by components analysis, surface porosity and TGA analysis. One AC sample was selected for elemental mercury capture tests in a labscale drop tube reactor with air flow. The results show that low-cost and effective activated carbon could be produced by co-process of chicken waste and coal with benefits to increase char yields. The higher removal efficiency is assumed that some activated species of chlorine and sulfur contained in the activated carbon can be of benefit to elemental mercury capture. However, the assumed capture mechanism should be proved by the further investigation of detailed surface characteristics. 4-4 Characterization Mercury Transport and Deposition in Ohio River Valley Region Myoungwoo Kim, Kevin Crist, Ohio University, USA Rao Kotamarthi, Argonne National Laboratory, USA Ohio University, in collaboration with Argonne National Laboratory, CONSOL Energy, Advanced Technology Systems, Inc (ATS) as subcontractors, is evaluating the impact of emissions from coal-fired power plants in the Ohio River Valley region as they relate to the transport and deposition of mercury, arsenic, and associated fine particulate matter. This evaluation involves two interrelated areas of effort: ambient air monitoring and regionalscale modeling analysis. The scope of work for the modeling analysis includes (1) development of updated inventories of mercury and arsenic emissions from coal plants and other important sources in the modeled domain; (2) adapting an existing 3-D atmospheric chemical transport model to incorporate recent advancements in the understanding of mercury transformations in the atmosphere; (3) analyses of the flux of Hg 0 , RGM, arsenic, and fine particulate matter in the different sectors of the study region to identify key transport mechanisms; (4) comparison of cross correlations between species from the model results to observations in order to evaluate characteristics of specific air masses associated with longrange transport from a specified source region; and (5) evaluation of the sensitivity of these correlations to emissions from regions along the transport path. This will be accomplished by multiple model runs with emissions simulations switched on and off from the various source regions. The modeling analysis is currently on-going. However an analysis of the base case runs will be presented including mercury wet-deposition patterns for the Ohio River Valley. 4-5 Field Evaluations of Carbon Sorbents Nicholas R. Pollack, Calgon Carbon Corporate, USA Calgon Carbon Corporation has investigated a series of carbon sorbents for the removal of mercury from flue gas streams of coal-fired power plants. Pilot studies were conducted at a commercial power plant together with Apogee Scientific, Inc. The results represent the performance of the sorbents under real conditions using an actual flue gas stream. A number of parameters were studied: carbon substrate, particle size, impregnants, pore volume, and surface modifications. A follow-up study was conducted with the most promising candidates in order to maximize the performance and minimize the cost of the sorbent. Greater than 90% mercury removal was achieved with the best sorbents at normal injection rates. Calgon Carbon Corporation will present the results of these studies.
Page 1 and 2: TABLE OF CONTENTS Oral Sessions Pag
Page 3: 1-1 SESSION 1 GASIFICATION TECHNOLO
Page 7 and 8: 5-5 Enhanced Hydrogen Production wi
Page 9 and 10: derived synthesis gases employing i
Page 11 and 12: Several physical adsorbents, partic
Page 13 and 14: 13-1 SESSION 13 GASIFICATION TECHNO
Page 15 and 16: promising Clean Coal technologies u
Page 17 and 18: high selectivity (theoretically pro
Page 19 and 20: 19-3 Development of Highly Efficien
Page 21 and 22: The Aim of the project is the impro
Page 23 and 24: 24-3 Development of Fluidizable Lit
Page 25 and 26: the classical Lurgi-gasifcation pro
Page 27 and 28: 28-5 A Kinetic Approach to Catalyti
Page 29 and 30: turbine cycles. The models provide
Page 31 and 32: up to 290 psia and temperatures up
Page 33 and 34: 35-2 Development of Iron-Based Pero
Page 35 and 36: features of the BGL 1000 technology
Page 37 and 38: Heat-exchangers, particle filters,
Page 39 and 40: 41-4 Using Fly Ash-Based Foundry Co
Page 41 and 42: ocks using elemental ratios. Data f
Page 43 and 44: 600-900°C. Changes in the amount o
Page 45 and 46: ATL process has three stages, namel
Page 47 and 48: commercial-scale gasifier was shutd
Page 49 and 50: 52-5 Pilot-Scale Demonstration of U
Page 51 and 52: POSTER SESSION 1 COMBUSTION TECHNOL
Page 53 and 54: experimental data available in lite
Page 55 and 56:
activation. It was concluded that C
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